This invention relates to radiation detectors and, more particularly, to radiation detectors that provide the direction of the source of the radiation. This invention was made with government support under Contract No. W-7405-ENG-36 awarded by the U.S. Department of Energy. The government has certain rights in the invention.
There are numerous instances where it is desirable to determine the direction from an observer of a radiation source, e.g., fast neutrons, etc. A wide range of techniques has been used to provide detectors with a directional capability. One commonly used directional detector is a collimated instrument where shielding is used to restrict the angular acceptance of radiation by the detector and to reduce background contributions from other directions. Thus, a maximum output is obtained when an aperture in the shielding is aligned with a radiation source. In some instances, a rotating collimator aperture or multiple apertures are used to obtain source direction information.
Other directional detector designs use filament-type detectors to obtain directional information. E. L. Chupp et al., "A Direction Neutron Detector for Space Research Use", IEEE Transactions on Nuclear Science NS-13, pp. 468-477 (Feb. 1966), teaches aligning the filament axes toward the radiation source to provide a directional output. R. F. Stetson et al., "A Directional Scintillation Counter for Neutrons", 6 Nuclear Instruments and Methods, pp. 94-95 (1960), suggests the use of an array of filament arrays that use the forward-peaked angular distribution of protons from n-p collisions to obtain directional effects.
In many applications, weight and portability are important considerations in selecting a detector. For example, space applications require light weight devices, and simplicity is desired since repair is not feasible. These same considerations are also applicable to mobile detectors, particularly hand held devices or devices that might require access to restricted locations.
The present invention addresses these considerations and a directional detector is formed from four unshielded detectors where a simple analysis of the detector outputs provides a vector indicating the direction and strength of a radiation source.
Accordingly, it is an object of the present invention to provide an uncollimated directional detector.
It is another object of the present invention to enable the direction of a radiation source to be determined from a simple algorithm.
Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.